A search was made for dense deposits in sites other than kidney with the use of skin biopsy specimens obtained from patients with dense-deposit disease (DDD) and tissues from autopsy material. Dense deposits were not present in basement membranes at the epidermal-dermal junction or around dermal capillaries in three skin biopsy specimens. Three cases of DDD involving the kidneys (from 1937, 1940, and 1945) were found on reviewing 200 autopsy cases in which the cause of death was renal failure. Paraffin blocks of various tissues from these cases were examined by electron microscopy. Dense deposits were noted in sinusoidal basement membranes of the spleen in the two cases in which spleen was available. No dense deposits were found in brain, heart, lungs, liver, adrenals, or pancreas. We conclude that DDD involves the kidneys and spleen.